Pan Car Weight

[DekelzMan]

As per our discussion last night at the AGM I was wondering if those of us that currently have cars, be they old school or new generation, could start posting their car weights race ready. This means, with whatever battery you're planning to run, what motors, speed controls and bodies and tires installed.

My Darkside iForce with everything installed (LiPo and Brushed 19T) was about 85 gms light. I added 6 tungsten plates into the battery slots by sandwiching them between my Dekelz chassis skin and a LiPo tray I made for the battery to slip into. The car is now sitting at 1208 gms.

Please post your personal results here when you get a moment.

BTW, the conversion from ounces to grams is 1 oz = 28.35 gm.

Mick

[RC51]

Hey, Mick.

My cement truck of a Pan Car came in at 1342 Grams using NiMh, an Futaba 9550s servo, Brushless motor, Novak GTB (pig), Spektrum mini receiver and a body.

P.

[Shawn68z]

My CRC Chassis, with GTB 10.5, Sprektrum 3000 RX, Trakpower 4900, with GRP wheels.  980 grams.

With the body, and transponder, I need to add about 50-60 grams.

Shawn.

[Tom]

Just weighed my machine un-changed from last year, with 3300's.

1270 grams -- all it needs is a pinion gear.

[Blake]

CRC Gen-X 10
235mm widening kit installed
19T brushed motor
Trackpower 4900 LiPo battery
Brand new, un-trued Jaco tires front and rear
Mid/small sized electronics
Fairly heavy wiring with Deans plugs and lots of 13awg wire
Completely ready to run with body and personal transponder

1120g

I had to bolt on 6 of Phil's tungsten plates (about 14g each) to bring the weight up over 1200g.


Blake

[Tom]

So from walking around the pits on the 1st race day, it seems as though the cars running nickel batteries tended to be around 1300 grams, and the lithium powered cars tended to be around 1200 grams (with exceptions, obviously).  We had 20 pan cars racing this past weekend, which is far more data than the few posts above.

This sounds to me like the cars with the power advantage (7.4 volts nominal or 3% power advantage) also have the weight advantage (100 grams less, or 8% weight advantage).

Earlier on we were discussing methods of trying to even out the different technologies by giving the lithium cars a weight penalty if need be to even out the performance.  I don't think we intended to give the lithium cars both a power and weight advantage over the nickel cars.

Should we be re-thinking the Pro 10 class weight limit after seeing some real-world car weights?  I know several cars had a definite performance advantage over mine, and I don't want to have to buy new equipment to be competitive -- our motivation in the Pro 10 class was to ensure both technologies could compete together.

I know it's early in the season, but it might be nice to try to get on an even footing early on so we can do fine-scale tweaking mid-season, rather than having a big disparity in weight among the cars for a big chunk of time.

What do you all think?

[Shawn68z]

So from walking around the pits on the 1st race day, it seems as though the cars running nickel batteries tended to be around 1300 grams, and the lithium powered cars tended to be around 1200 grams (with exceptions, obviously).  We had 20 pan cars racing this past weekend, which is far more data than the few posts above.

This sounds to me like the cars with the power advantage (7.4 volts nominal or 3% power advantage) also have the weight advantage (100 grams less, or 8% weight advantage).

Earlier on we were discussing methods of trying to even out the different technologies by giving the lithium cars a weight penalty if need be to even out the performance.  I don't think we intended to give the lithium cars both a power and weight advantage over the nickel cars.

Should we be re-thinking the Pro 10 class weight limit after seeing some real-world car weights?  I know several cars had a definite performance advantage over mine, and I don't want to have to buy new equipment to be competitive -- our motivation in the Pro 10 class was to ensure both technologies could compete together.

I know it's early in the season, but it might be nice to try to get on an even footing early on so we can do fine-scale tweaking mid-season, rather than having a big disparity in weight among the cars for a big chunk of time.

What do you all think?

I think you should drill out your chassis to make it lighter.  :wink:


You are definately right Tom. Maybe an increase in minimum weight should be consdered. 1350?

The only other question I would bring to this is were all the fast cars running 10.5? or were some of the fast cars also running 19T ? The Lipo might not be the only performance advantage in the faster cars.

Shawn.

[WhoDoYouThink]

Hey Tom, maybe you should have actually worked on your car before bringing it out to race,  instead of just blowing the dirt and dust off of it and throwing a pinion gear at it! ;-)

Maybe, just maybe, your NiMh are junk! Hmmmm?

How did the lap times look, comparatively speaking?
IE: Brushed versus brushless, NiMh versus LiPo, and any of the various  combinations of the two technologies? What about the different tire combos?

Before you go and get ideas about changing the weight rules because you were slow, don't you think it would be a good idea to look a little deeper into the situation?

Do we have the race results/lap times somewhere? Do we have information as to who ran what?

[DekelzMan]

I think it's waaay too early to be thinking about changing things up. The point of having two separate points seasons was for this early one to be the test bed where we as a group learn all there is to know about the new technologies as well as the new PanCar drivers getting some much needed track time and learn how to tune their cars.

You can't possibly expect years old 3300's to be competitive against any new battery, regardless of their chemistry. I'm more than happy to even the playing field but we need to be very careful when formulating this penalty system because come Speed Weekend we will not be penalizing out-of-towners just because locally some are too thrifty to modernize.

So how are we going to decide who needs to add weight anyway? Based on what criteria? If someone happens to nail the right tire combo and have a more aerodynamic body that suits a particular track layout two weeks in a row, will that constitute a weight penalty? How far down the grid do we decide to take this restriction system? Will it be based on your main standings only?How often do we revisit the restrictions, every week?

A worthy discussion can now commence. Enlighten me

Mick

[RC51]

FYI, Mick and I have been testing a fair bit between Vancouver, Kamloops and Victoria and both he and I agree that battery chemistry will be the major variable over everything else. I can guarantee you that a 10.5 BL can out perform a brushed 19T motor using the same battery chemistry (assuming constant performance factors). However, a brushed 19T with a LiPo will stomp a brushless with NiMh from what we have been able to determine. Anecdote be damned - the math just proves it clearly and you can see it on the track. So, the ultimate combo should be a BL and LiPo assuming you can keep the motor cool. Getting the power to the ground, however, trumps everything.

So, if as Mick suggests, a dog of a 19T running 2400 NiCds but is dialed on a particular week or the next, should that car be penalized by adding weight for the next week? Waaaaaay too many variables for that. Our track layout is different week to week as well so it is really a canundrum. The spec should be the equalizing factor and not over-performance/under-performance of any given car assuming the power and body specs are equally agreed to from the outset.

[Blake]

Tom, I can lend you a more modern NiMH battery this weekend.  It's gotta be better than those 3300s you're running.  I used it last summer and it worked great.  Also, as Nick suggests, it might help to give your motor a touch up.  Then hopefully you'll be more in the ballpark.

I agree that a LiPo and/or brushless weight penalty will *likely* be needed, but as all others have said here, it's probably a little early to be making any decisions yet.

Also, let's swap cars for a few laps this weekend, for curiousity's sake.


Blake

[RC51]

I agree that a LiPo and/or brushless weight penalty will *likely* be needed, but as all others have said here, it's probably a little early to be making any decisions yet.Blake

But to Mick's point, what would you be penalizing and is it fair or equal to all others in the same situation? If all 19T NiMh beat (how many??) LiPo BL on a given day, would you still penalize BL/LiPo for losing? Or would you penalize NiMh/19T for winning? What's the point? From what I see, the risk is one of penalizing someone for driving well and not for the performance of their power plant. Don't get me wrong, I see the aim here, and it's virtuous. But is a penalty in order given we're all over the map with respect to skill, performance, cars, setup and electronics?

I say we set a reasonable (median?) minimum weight and go for it. 1200 Grams was set but we could simply throw all of the cars on the scale during practice and figure it out, set the standard for the following week and see how it goes.

Thoughts?

[Blake]

Hey Phil,


I agree.  There are so many factors on any given race day that it would be foolish to start assigning penalties after one race.  I think we need to race a couple more times to see if we can find some "trends".  It will be tough analysis given the different skill levels of all the drivers and the different equipment employed by each.

That's why I'd like to try swapping cars with Tom for a half race or so.  We've done this in the past with 12th Scale and it can be quite telling.  Of course, I'd really only be willing to try this experiment after we freshen up his motor and install a modern-ish battery!


Blake

[WhoDoYouThink]

Tom,  stick some new spacers behind those worn out brushes already! LOL

One Race Day under only slightly better than Marginal Conditions with various battery/motor/chassis/tire set-ups shouldn't be used as a baseline for changing anything, IMHO.

[Tom]

I've only skimmed over these posts, but it seems as though my point was missed.  I'll hopefully post the race results soon.

A LiPo/19 turn car came 1st, and a NiMH/19 turn car (3300's to boot) came 2nd, so I'm not looking for excuses for my lack of speed.  You'll be able to see that my fastest lap time was something like 6th fastest in the main even though I finished 2nd.

My point was that, in general, only the LiPo cars are near the class minimum weight, and the NiMH cars tend to be over by 8% or so.  I was thinking maybe we could start the season on a more even keel with a realistic minimum that doesn't penalize NiMH drivers, rather than giving one class a weight penalty (which we effectively have right now, in the opposite direction that intuition suggests we would have if we were to mandate one).

From my understanding, someone pulled the proposed minimum of 1200 grams out of the air, and I'm just suggesting that we might consider making it 1300 grams instead.  This way, most cars would be near the minimum, rather than the current situation where only the LiPo cars are near the minimum.

Right now, I'm suggesting ALL NiMH cars are around 100 grams over, and MOST LiPo cars are around the minimum.  If we go to 1300 grams, then MOST NiMH cars will be around the minimum, and MOST LiPo cars would be around the minimum.  That sounds like a fair starting point to the season to me.

If you LiPo guys think you need a 100 gram advantage to run against a 3300 equipped 19 turn car, then bring it on, but I don't think everyone running NiMH needs the challenge.

I've got better batteries that I can use too, so I'm suggesting this change based on real-wrold observed weights, rather than because I think I'm too slow.